I like riding my bike in my regular clothes. I hate having my full skirts blow up and show my knickers. I can't ride a bike in a regular slip as they are usually cut quite narrow and it is hard to get onto the saddle.
I modified a pattern for pyjama bottoms to that there was only one seam; on the side. I did not want any seams chafing against the saddle of my bike. I used bemberg lining as I like it so much better than any other kind.
I like this garment so much, I made another it in some other colours and I have given away the rest of my slips. I even wear it under trousers to prevent binding when I am wearing tights on cold days.
I have the full instructions here on Instructables if you are at all interested.